High intensity workouts inducing migraines??

Hi guys,

I'm curious if any trainers have every heard of my situation and maybe have a solution.

I love spin class and interval sprints, but it seems like every single time I end up with a migraine hours later.

I pretty much have my non-workout migraines under control, I know my triggers (excess estrogen, red wine, etc), and my doctors have me on sumatriptan to treat attacks. Full disclosure: I also have hashimotos thyroiditus, I take synthroid every day and stay on top of my hormone levels.

So far my doctors have suggested it was exercise induced asthma - but an inhaler did not have any effect in preventing or treating these attacks. They also ruled out anemia, and diabetes.

I've tried on my own to pinpoint what goes wrong by wearing a heart monitor - it would seem that the minute I exceed 175 bpm, my throat and nasal passages swell, my eyes get light sensitive, and I need to have an emergency cool down.

I stopped exceeding high rates and started giving myself generous cool down periods before hard pushes, and it helps only during the class. Like clockwork, 2 hours after I feel euphoric and strong for completing spin, my upper respiratory starts to slowly swell, it feels like the blood vessels are expanding in my ears and behind my eyes. I get light sensitive and then suddenly full blown migraine that knocks me out for the night. It seems to be triggered at my first meal intake after class.

I tried experimenting with eating a banana before class for potassium. Still got a migraine.
Tried an apple. Still got a migraine.
Icey cold showers for total cool down. Still migraine.

Am I missing something obvious that trainers know about? Should I try Gatorade gel in the middle of class?
Hoping someone has heard of this situation before! I really want to be able to spin!